scholarly journals Heating Performance Characteristics of an Electric Vehicle Heat Pump Air Conditioning System Based on Exergy Analysis

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2868 ◽  
Author(s):  
Xingwang Tang ◽  
Qin Guo ◽  
Ming Li ◽  
Mingzhe Jiang
Keyword(s):  
Ambient Temperature ◽  
Electric Vehicle ◽  
Flow Rate ◽  
Air Conditioning ◽  
Air Flow ◽  
Exergy Destruction ◽  
Air Flow Rate ◽  
Air Conditioning System ◽  
Heating Capacity ◽  
Expansion Valve

In this paper, a heat pump air conditioning system (HPACS) with refrigerant R134a based on the functional requirements of battery electric vehicle is designed and tested. Experiments were conducted to evaluate the effects of different ambient temperature, air flow rate of internal condenser, expansion valve (EXV) opening and compressor speed. The results demonstrate that air flow rate of internal condenser, EXV opening and compressor speed have important impact on heating capacity, compressor power consumption and coefficient of performance (COP) under several ambient temperatures. To verify the HPACS can also provide the heating capacity required by the battery electric vehicle cabin in cold climate, the system was also tested under a −5 °C ambient temperature, it was found that the heating capacity is 3.6 kW and the COP is 3.2, demonstrating that the system has high energy efficiency. In addition, heating process analysis of the HPACS under lower temperature is studied by exergy principle. The results indicate that compressor is the highest exergy destruction in all components, accounting for 55%. The percentage of exergy destruction in other components is about 28%, 12% and 5% for the expansive valve, condenser, and evaporator. Furthermore, air flow rate of internal condenser, ambient temperature and expansion valve opening have important impact on exergy destruction and exergy efficiency of the HPACS.

scholarly journals Coupling Effect of Air Flow Rate and Operating Conditions on the Performance of Electric Vehicle R744 Air Conditioning System

2021 ◽  
Vol 11 (11) ◽  
pp. 4855
Author(s):  
Anci Wang ◽  
Jianmin Fang ◽  
Xiang Yin ◽  
Yulong Song ◽  
Feng Cao ◽  
...  
Keyword(s):  
Electric Vehicle ◽  
Flow Rate ◽  
Air Conditioning ◽  
Volume Flow Rate ◽  
Air Flow ◽  
Volume Flow ◽  
Air Flow Rate ◽  
Air Volume ◽  
Discharge Pressure ◽  
Air Conditioning Systems

The air flow rate on the gas cooler side is one of the key parameters affecting the performance and running safety of transcritical CO2 electric vehicle air conditioning systems. After experimentally analyzing the effects of the air volume flow rate in the gas cooler on the cycle parameters and system performance, a novel method to evaluate the optimal air flow rate was proposed. In addition, the effect of the gas cooler air volume flow rate on the key performance parameters of the system (e.g., optimal discharge pressure) was explored. Finally, the coupling effects of the compressor speed, ambient temperature and optimal air flow rate on the system performance was also exhaustively assessed. It was found that as the discharge temperature, the CO2 temperature at the gas cooler outlet and the discharge pressure did not vary more than ±2%, the corresponding gas cooler air volume flow rate was optimal. For the single-row and dual-process microchannel evaporator used in this work, the recommended value of the optimal gas cooler air volume flow rate was 2500 m3·h−1. The results could provide reference for the fan speed design of electric vehicle CO2 air conditioning systems, especially for the performance under idling model.

scholarly journals Development of an air conditioning system with individual regulation of temperature and air flow rate in a compartment of a passenger car

2021 ◽  
Vol 80 (1) ◽  
pp. 30-34
Author(s):  
G. M. STOYAKIN ◽  
A. V. KOSTIN ◽  
S. N. NAUMENKO
Keyword(s):  
Air Temperature ◽  
Flow Rate ◽  
Air Conditioning ◽  
Air Flow ◽  
Three Dimensional ◽  
Air Flow Rate ◽  
Passenger Cars ◽  
Air Conditioning System ◽  
Air Supply ◽  
Individual Regulation

Maintaining optimal parameters of the microclimate in the car along the route is the most important requirement for the passenger’s travel. In the 1st class passenger cars, maintaining optimal microclimate parameters is achieved through the operation of the air conditioning system, which provides individual regulation of the air temperature in each compartment. Individual air temperature control systems used in air conditioning systems are divided into two groups: active and passive.The article proposes for consideration a combined active-passive system with a separate air supply with a lower and higher temperature compared to the temperature maintained in the compartment and the installation of individual induction terminals, which makes it possible to increase the efficiency of individual regulation of air parameters in the compartment.To assess the uniformity of temperature distribution and air flow rate over the car volume with the proposed control scheme, a three-dimensional modeling of the distribution of these parameters in the compartment was carried out on the basis of Autodesk CFD software.The given simulation results indicate the uniformity of temperature and air flow rate distribution over the compartment volume, which makes it possible to characterize the proposed system as sufficiently energy efficient, easy to operate and reliable in operation.

scholarly journals Heat pump air conditioning system for pure electric vehicle at ultra-low temperature

2014 ◽  
Vol 18 (5) ◽  
pp. 1667-1672 ◽  
Author(s):  
Hai-Jun Li ◽  
Guang-Hui Zhou ◽  
An-Gui Li ◽  
Xu-Ge Li ◽  
Ya-Nan Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Electric Vehicle ◽  
Heat Pump ◽  
Air Conditioning ◽  
Heating System ◽  
Experimental Results ◽  
Air Conditioning System ◽  
Discharge Temperature ◽  
Heating Capacity ◽  
Environment Temperature

When the ordinary heat pump air conditioning system of a pure electric vehicle runs at ultra-low temperature, the discharge temperature of compressor will be too high and the heating capacity of the system will decay seriously, it will lead to inactivity of the heating system. In order to solve this problem, a modification is put forward, and an experiment is also designed. The experimental results show that in the same conditions, this new heating system increases more than 20% of the heating capacity; when the outside environment temperature is negative 20 degrees, the discharge temperature of compressor is below 60 degrees.

Numerical and experimental investigation on the air flow characteristics of heating, ventilation, and air-conditioning module for a small electric vehicle

2019 ◽  
Vol 234 (6) ◽  
pp. 1597-1609
Author(s):  
Kang Li ◽  
Hao Gao ◽  
Peng Jia ◽  
Lin Su ◽  
Yidong Fang ◽  
...  
Keyword(s):  
Heat Pump ◽  
Flow Rate ◽  
Air Conditioning ◽  
Air Flow ◽  
Flow Characteristics ◽  
Cold Climate ◽  
Airflow Rate ◽  
Positive Temperature ◽  
Air Flow Rate ◽  
Pump System

In electrical vehicles, replacing positive temperature coefficient heater as heat source with an air source heat pump could improve the driving range and decrease energy consumption in cold climate. Design of the heating, ventilation, and air-conditioning module for heat pump system has a significant influence on its performance in each working mode. A newly designed heat pump heating, ventilation, and air-conditioning module was introduced in this paper. The air flow characteristics of the heat pump heating, ventilation, and air-conditioning module in four working modes were analyzed, and the air flow rate and wind resistance were obtained by numerical simulation. Experiments were also conducted for validating its airflow rate in each working mode. Results of these experiments show that some unfavorable phenomena such as flow maldistribution and vortex inside the heat pump heating, ventilation, and air-conditioning module exist, which could lead to insufficient utilization of the heat exchange area of heat exchangers and the generation of aerodynamic noise. Furthermore, the air flow rate of the original heating, ventilation, and air-conditioning module was also measured for comparison, and the designed heat pump heating, ventilation, and air-conditioning module shows nearly 15–20% decrease in each working mode.

scholarly journals Numerical Simulation and Optimization of Waste Heat Recovery in a Sinter Vertical Tank

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 385 ◽  
Author(s):  
Chenyi Xu ◽  
Zhichun Liu ◽  
Shicheng Wang ◽  
Wei Liu
Keyword(s):  
Heat Transfer ◽  
Power Consumption ◽  
Flow Rate ◽  
Heat Dissipation ◽  
Waste Heat ◽  
Air Flow ◽  
Particle Diameter ◽  
Exergy Destruction ◽  
Air Flow Rate ◽  
Simulation And Optimization

In this paper, a two-dimensional steady model is established to investigate the gas-solid heat transfer in a sinter vertical tank based on the porous media theory and the local thermal non-equilibrium model. The influences of the air flow rate, sinter flow rate, and sinter particle diameter on the gas-solid heat transfer process are investigated numerically. In addition, exergy destruction minimization is used as a new principle for heat transfer enhancement. Furthermore, a multi-objective genetic algorithm based on a Back Propagation (BP) neural network is applied to obtain a combination of each parameter for a more comprehensive performance, with the exergy destruction caused by heat transfer and the one caused by fluid flow as the two objectives. The results show that the heat dissipation and power consumption both gradually increase with an increase of the air mass flow rate. Additionally, the increase of the sinter flow rate results in a decrease of the heat dissipation and an increase of the power consumption. In addition, both heat dissipation and power consumption gradually decrease with an increase of the sinter particle diameter. For the given structure of the vertical tank, the optimal operating parameters are 2.99 kg/s, 0.61 kg/s, and 32.8 mm for the air flow rate, sinter flow rate, and sinter diameter, respectively.

Analysis of Heat Transfer From a Photobioreactor

2016 ◽  
Author(s):  
Gary A. Anderson ◽  
Sarmila Katuwal ◽  
Anil Kommareddy ◽  
Stephen Gent
Keyword(s):  
Relative Humidity ◽  
Ambient Temperature ◽  
Heat Loss ◽  
Growth Medium ◽  
Flow Rate ◽  
Air Flow ◽  
Air Flow Rate ◽  
Medium Temperature ◽  
Reactor Volume ◽  
Light Passing

A photobioreactor (PBR) was operated for sixteen days producing S. Leopoliensis. The PBR was lit by two LED panels, one on each of the long sides of the PBR. The PBR dimensions were nominally 51mm by 273mm with a height of 319mm (273mm liquid depth). Each LED panel was powered at 14.1W (11.2V and 1.26A). Measurements of ambient temperature, ambient relative humidity, water loss from the PBR, relative humidity of the exhaust gas from the PBR, air flow rate through the PBR, air pressure in the plenum, growth medium temperature, and LED panel temperature were made approximately daily. Measurements show that the growth medium (water) temperature was relatively insensitive to the ambient temperature which varied from 22.7C to 33.6C. The medium temperature ranged from 23.9C (beginning of the test) to 40.6C. The medium temperature mirrored the LED panel temperature staying 2–4C below the LED panel temperature after the first day. The elevated LED panel temperature was likely due to the inefficiency of the LED lights and the fact that much of the light passing through the reactor volume was incident on the LED panel on the opposite side of the reactor. The panels are black in color and absorbed a significant portion of the light passing through the reactor volume. The air flow rate through the PBR ranged from 1.33×10−5m3/s to 1.67×10−5m3/s. The parallel between panel temperature and PBR medium temperature indicate that the amount of air moving through the PBR was insufficient to affect the medium temperature significantly. The heat loss from the PBR to the ambient environment was also small likely due to the small area available to heat loss to the environment when the PBR walls with the LED panels are excluded. The LED panels covered nominally 88% of the PBR reactor volume area. The measured data and measurements of light intensity passing through the two short walls of the panel will be used to estimate heat loss parameters of the PBR. The exhaust air from the PBR varied from 42.6% to 99.1% with the higher measurements occurring days 6–11. Estimates of the energy stored in the algal biomass are also evaluated in the analysis.

scholarly journals A Study on the Application Possibility of the Vehicle Air Conditioning System Using Vortex Tube

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5227 ◽  
Author(s):  
Younghyeon Kim ◽  
Seokyeon Im ◽  
Jaeyoung Han
Keyword(s):  
Heat Exchange ◽  
Low Temperature ◽  
Flow Rate ◽  
Air Conditioning ◽  
Vortex Tube ◽  
System Simulation ◽  
Air Flow Rate ◽  
Exchange Method ◽  
Air Conditioning System ◽  
Air Conditioning Systems

Since refrigerants applied to vehicle air conditioning systems exacerbate global warming, many studies have been conducted to supplement them. However, most studies have attempted to maximize the efficiency and minimize the environmental impact of the refrigerant, and thus, an air conditioning system without refrigerant is required. The vortex tube is a temperature separation system capable of separating air at low and high temperatures using compressed air. When applied to an air conditioning system, it is possible to construct an eco-friendly system that does not use a refrigerant. In this paper, various temperature changes and characteristics of a vortex tube were identified and applied to an air conditioning system simulation device. Additionally, an air conditioning system simulation device using indirect heat exchange and direct heat exchange methods was constructed to test the low-temperature air flow rate (yc), according to the temperature and pressure. As a result of the experiment, the temperature of the indirect heat exchange method was found to be higher than the direct heat exchange method, but the direct heat exchange method had low flow resistance. As a result, the direct heat exchange method can easily control the temperature according to the pressure and the low-temperature air flow rate (yc). Therefore, it was judged that the direct heat exchange method is more feasible for use in air conditioning systems than the indirect heat exchange method.

scholarly journals Minimization of fan energy consumption in ventilation and (or) air-conditioning systems as an optimization calculus of variations

2019 ◽  
Vol 116 ◽  
pp. 00033
Author(s):  
Michał Karpuk
Keyword(s):  
Energy Consumption ◽  
Calculus Of Variations ◽  
Flow Rate ◽  
Air Conditioning ◽  
Air Flow ◽  
Rate Function ◽  
Hazardous Substances ◽  
Air Flow Rate ◽  
Starting Conditions ◽  
Air Conditioning Systems

The article presents an optimization calculus of variations of fan energy consumption in ventilation and (or) air-conditioning systems. It defines an air flow rate function that depends on the time of operation in the defined room size, starting conditions and the function of hazardous substances emission rate in the room. The differential form of air flow rate dependence on density of hazardous substances allows to establish a connection between air pollution in the room and a fan air flow rate, i.e. fan energy consumption. Creating a fan energy model experiment in the room in different conditions allows to minimize energy consumption to 5–30% depending on existing conditions.

Numerical Modeling of Perforated Tile Flow Distribution in a Raised-Floor Data Center

2007 ◽  
Author(s):  
Emad Samadiani ◽  
Jeffrey Rambo ◽  
Yogendra Joshi
Keyword(s):  
Numerical Modeling ◽  
Flow Rate ◽  
Data Center ◽  
Air Conditioning ◽  
Air Flow ◽  
Flow Distribution ◽  
Air Flow Rate ◽  
Tile Flow ◽  
Operating Points

This paper is centered on quantifying the effect of computer room and computer room air conditioning (CRAC) unit modeling on the perforated tile flow distribution in a representative raised-floor data center. Also, this study quantifies the effect of plenum pipes and perforated tile porosity on the operating points of the CRAC blowers, total CRAC air flow rate, and its distribution. It is concluded that modeling the computer room, CRAC units, and/or the plenum pipes could change the tile flow distribution by up to 60% for the facility with 25% open perforated tiles and up to 135% for the facility with 56% open perforated tiles.

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